The present invention relates to a method and device to determine the alignment for the insertion of an instrument such as a pin, rod, nail, screw, wire, drill bit, or other implant into bony tissue using x-ray or fluoroscopy or the like to stabilize fractures or other bony tissue defects. More particularly, the method and device is designed for use by a surgeon to properly determine the point and trajectory of insertion of said instrument into a particular bone mass using an x-ray or fluoroscopic imaging device without the need to otherwise make multiple attempts to properly insert the instrument, such as a nail, pin, rod, screw, wire, drill bit, or other implant into the bony tissue.
Every year, in the United States and worldwide, large numbers of surgical procedures are performed in which an instrument, such as a nail, pin, rod, screw, wire, drill bit, or other implant is inserted into a bony tissue mass to stabilize a fracture or defect in such bony tissue mass. The nail or screw strengthens the bone and holds the parts of the bone together. For example, such a technique is used to fix a hip fracture. Hip fracture fixation with either compression hip screws (CHS) or intramedullary interlocking nails is one of the most common orthopedic surgical procedures. The surgeon""s goals are accurate reduction and stabilization of the fracture until bony union occurs. For purposes of illustration herein, examples regarding the insertion of a pin into the proximal femur of a person will be referred to. This should in no way be interpreted as a limitation on the scope of this invention. Rather, the present invention includes, without limitation, devices used for insertion of instruments, such as pins, screws, rods, nails, wires, drill bits, or other implants into any bony tissue of a person or animal.
In one such surgical procedure, an incision is made through the skin of the hip to expose the femur starting at the tip of the greater trochanter. Using visual landmarks, the surgeon drills a guide-pin across the fracture into the femoral head. The surgeon checks the. positioning of the guide-pin with an x-ray or fluoroscopic imaging device to determine if the positioning of the guide-pin is acceptable. If it is not, the surgeon must extract the guide-pin and reevaluate the insertion point and trajectory, then reinsert the guide-pin until its positioning is acceptable. When the guide-pin is in an acceptable position, a lag screw is advanced over the guide-pin into the femoral head to secure the bone for healing. A side plate is placed over the lag screw extender and secured to the lag screw and the femur for support and to compress the fracture. (See FIG. 2a).
Another means of securing a femoral neck fracture is with the use of an intramedullary locking nail. In that surgical procedure, an incision is made over the trochanteric region. The entry point is prepared using an awl. A guide wire is inserted into the femur and the intramedullary nail is inserted over the guide wire into the femur. A device is used to align a lag screw through a guide sleeve which is brought into contact with the femur. The screw is visually oriented and the surgeon drills a guide-pin across the fracture into the femoral head. The surgeon checks the positioning of the guide-pin with an x-ray or fluoroscopic imaging device to determine if the positioning of the guide-pin is acceptable. If it is not, the surgeon must extract the guide-pin and reevaluate the insertion point and trajectory, then reinsert the guide-pin until its positioning is acceptable. When the guide-pin is in an acceptable position, lag screw is advanced over the guide-pin, through an opening in the proximal portion of the intramedullary nail, and into the femoral head. The guide-pin is extracted and the intramedullary nail is secured by drilling screws through openings in the distal portion of the intramedullary nail.
An important part of both procedures is the placement of a compression or lag screw from the lateral side of the femur, through the femur, passing through the femoral neck, and into the femoral head. Inaccurate placement of the screw can lead to being misaligned with respect to the femoral head (see FIG. 1).
To avoid this, surgeons commonly spend a significant portion of their operating time iteratively inserting, checking, removing, and re-inserting a guide-pin over which the screw will be passed until accurate positioning within the femoral head is achieved.
Surgeons typically use fluoroscopic image intensifiers to determine the accuracy of their guide-pin placement in two planes of view, the anterior-posterior (xe2x80x9cAPxe2x80x9d) and the medial-lateral (xe2x80x9cMLxe2x80x9d) (see FIGS. 3a and 3b). After satisfying themselves that the position of the guide-pin within the femur is accurate in one view, the fluoroscope is turned to the orthogonal view to check accuracy in that plane. If the wire or guide-pin is misplaced in the second view, the surgeon generally takes it out of the bone and reinserts it until satisfied with the position. By doing this, the surgeon loses reference of the initial view and must re-check the accuracy of the re-drilled guide-pin in both orthogonal views.
The surgeon repeats this process until reaching an acceptable position. This iteration takes time and results in greater x-ray exposure for patients and staff. Additionally, the process of inserting, removing, and reinserting the guide-pin could shred or seriously weaken the bone. The difficulty of guide-pin placement can also lead a frustrated surgeon to choose a less than optimal placement, putting the patient at risk for cut-out or faulty setting of the femoral head which could lead to settling of the femoral head.
U.S. Pat. No. 4,722,336 discloses a method and device to provide a three dimensional Cartesian coordinate of the target object using an x-ray or fluoroscopic imaging device and a radio-opaque targeting system. However, this method and device cannot be used where the fluoroscope cannot be aligned head-on with the guide piece and bony target.
U.S. Pat. No. 4,418,422 discloses an aiming device which is attached to an x-ray source. Similarly, this device cannot be used where a fluoroscope cannot be aligned head-on with the guide piece and the bony target. This device also cannot be used where the view-finder cannot be aligned head-on.
U.S. Pat. No. 4,976,713 discloses an aiming device that has a viewfinder with a radio-opaque component to align screws with anchoring holes in a centromedullar nail. This device also cannot be used where the viewfinder cannot be aligned head-on with the guide piece and bony target.
A similar limitation prevents the use in such circumstances of the device disclosed in U.S. Pat. No. 4,803,976, which discloses the use of parallel radio-opaque fluoroscopy target markers aligned parallel but one beside, not above, the other target marker.
Presently, where a fluoroscope cannot be used aligned head-on with the guide piece and the bony target, surgeons have used visual landmarks and repeated insertion to obtain appropriate placement. This increases the surgeon""s, the other medical personnel""s, and the patient""s exposure to x-ray radiation, increases the total operation time, and could lead to serious problems such as cut-out, as described above. There are currently no devices that are configured to be hand-held and easily used by the surgeon with an x-ray or fluoroscopic imaging device to accurately determine the proper entry point and trajectory for the insertion of an instrument, such as a pin, nail, screw, rod, wire, drill bit, or other implant. Also, there is currently no such targeting device which is adaptable and flexible to be used with different size patients which may require a targeting device to be custom adapted according to the patient""s size and body shape to accurately project the proper alignment for the instrument or implant to repair the particular bony target.
There has therefore been a long felt need among surgeons and other medical personnel in this field for a targeting device which would allow the surgeon to align the guide-pin in both the AP and ML positions before actually inserting the guide-pin so that the guide-pin can be inserted accurately on the first attempt with a variety of sizes and shapes of patients, particularly, but not limited to, where an x-ray or fluoroscopic imaging device cannot be aligned head-on with the guide piece and the bony target.
The targeting device is generally configured to be a hand-held and operated orthopedic instrument which typically has a body and an arm member. The body of the device is generally comprised of two pieces, although some embodiments have a body that is one piece. Where the body of the targeting device is comprised of generally two pieces, one piece is an angle guide and the other is a guide piece. The angle guide is toward the front portion of the body of the targeting device and during use, the angle guide is in contact with bony tissue of the patient. Although other shapes could be used, the angle guide is typically shaped with a cylindrical back portion and an angular front portion, which contacts the bony tissue. When the body of the targeting device is pressed against bony tissue of the patient, the body of the targeting device becomes oriented at an angle to the bony tissue corresponding to the angle of the front portion of the angle guide. The angle guide has a passageway which may be substantially in the center of the angle guide and is large enough so that a particular instrument or implant can be passed through it.
The passageway of the angle guide corresponds to the passageway of the guide piece so that the particular instrument or implant can readily pass through the entire body of the targeting device. The guide piece and the angle guide may be connected in various ways, e.g., fixed or rotationally. A rotational connection allows the guide piece to rotate while the angle guide remains fixed in place, gripping bony tissue. With a rotational connection, the guide piece may rotate freely, by indexing, or with friction. Another benefit of the two piece body is that a custom angle guide may be used to properly align the instrument or implant by providing the proper angle to obtain the optimal orientation.
Extending from near the back end of the targeting device""s body is an arm member. The purpose of the arm member is to extend outside the patient between the x-ray or fluoroscopic imaging device and the bony target. At some point on the arm member is at least one relatively radio-opaque target marker. The target marker is oriented between the x-ray or fluoroscopic imaging device and the bony target to indicate the placement of the instrument or implant when inserted into the bony target through the passageway of the body of the targeting device. For example, one embodiment has two relatively radio-opaque target markers which are parallel with one target marker aligned above the other such that when the two target markers overlap, the projected image is aligned to establish a plane that is co-planar with the targeting device""s passageway.
The present invention is also a method of using a targeting device to predict an appropriate entry point and trajectory into bony tissue through which an instrument, such as a pin, screw, rod, nail, wire, drill bit, or other implant is inserted. By providing a targeting device to a surgeon or other user which is comprised of: a body with a passageway and an angular end capable of gripping bony tissue; and an arm member with at least one relatively radio-opaque target marker which may be imbedded within the arm member. The user can predict the placement of said instrument, such as a pin, screw, rod, nail, wire, drill bit, or other implant before drilling it into place with the use of an x-ray or fluoroscopic imaging device. By manipulating the device around the axis of the body of the targeting device, the surgeon can predict the placement of the instrument or implant from various fluoroscopic views without repeatedly placing and removing the instrument or implant itself. This method may dramatically reduce both operating and fluoroscopy time, saving time and reducing the exposure of surgeons and other medical personnel to x-ray radiation.
These guides can be used with at least intramedullary interlocking nails and CHS implants and may be used in other surgeries requiring accurate implant or instrument placement relative to bony structures.
In a different embodiment, the present invention comprises a separate arm member which contains at least one relatively radio-opaque targeting member. Said relatively radio-opaque targeting member can be used to establish a plane that is co-planar with the base end of the arm member and indicates the projected placement of an implant or instrument, such as a pin, rod, nail, screw, or drill bit with the use an x-ray or fluoroscopic imaging device. Such arm member may be attached to or combined with another device to deliver the implant or instrument.
In another embodiment, the present invention comprises a separate angle guide with a passageway which may be used to align the placement of an instrument, such as a nail, pin, screw, rod, wire, drill bit, or other implant. The angle guide has a front portion and a rear portion. One variation has a back portion which is cylindrical in shape, and a front portion that is angled relative to a bony surface to orient a passageway which extends through the angle guide. Said angle guide may be used with other instruments to further align the placement of the instrument or implant. Said angle guide comprises a plurality of teeth which may be cut in a variety of ways. One preferred embodiment has a cylindrical cut. Said teeth may be angled inward from the sides of said angle guide toward the center of the angle guide to further grip a contoured bony tissue body, such as a femur.
The present invention also includes a kit containing the various components described above.